The Bullpup design allows you to hold it close to your body so even with a long silencer the gun does not feel over extended

But I would definitely say stick to the stock barrel or upgrade it to a tightbore as I noticed that even though I had a AK 455mm tightbore barrel in it, I found the small barrel a bit more maneuverable.

The whole point of the P90 is for sneaking or quick rush which I usually do and its great for stacking up and shooting in tight areas.

The only downfall is that on the battlefield you are pretty much alone as nobody has mags like you do and you would have to get pouches made for the P90 magazine.